The present invention relates to epoxysilanes and, in particular, to polyepoxysilanes curable in the presence of an 'onium salt catalyst when exposed to UV radiation.
Epoxysilicone polymers and epoxysiloxane monomers are readily prepared by platinum-catalyzed hydrosilation addition of olefin-epoxide monomers such as 4-vinyl cyclohexeneoxide (VCHO) and allylglycidyl ether (AGE) to the appropriate SiH-functional precursors, as described by E. P. Plueddemaun and G. Fanger, J. Amer. Chem. Soc., 81, 2632 (1959), and by R. J. Koshar et al., U.S. Pat. No. 4,313,988, among others. Further, it has been learned that certain rhodium hydrosilation catalysts are useful for synthesis of highly organofunctionalized epoxysilicone fluids and resins because they do not catalyze undesirable side reactions.
All of the references cited above teach the synthesis of epoxysilanes or epoxysiloxanes which are confined to mono-epoxy functionality attached to a silicon atom which in turn possess one or more Si-O bonds. Such materials can be represented as: ##STR1## where x.gtoreq.1 and E has the general formula ##STR2## where R is an aryl, alkyl cycloalkyl group, ether, or other hydrocarbon having from 1 to about 20 carbon atoms. Exemplary epoxides include: ##STR3##
Platinum catalysts commonly used to process these materials are not effective for synthesis of polyepoxyalkylsilanes such as E.sub.x Si R.sub.4-x where x&gt;1 and E is as defined above. Platinum catalysts commonly promote the addition of only one mole of olefin to an .dbd.SiH.sub.2 or --SiH.sub.3 species, which may account for the fact that polyepoxysilanes or polyepoxysilyl derivatives are not known.